Biomedical subjects

Carolyn J Teng

Publications and source records attributed to Carolyn J Teng.

3 recordsLinked to original sources

PubMed2006

Massive mechanical loss of microspheres with direct intramyocardial injection in the beating heart: implications for cellular cardiomyoplasty.

OBJECTIVE: Direct intramyocardial injection is a common route of donor cell administration for myocardial cell therapy. Studies have demonstrated a significant and rapid loss of implanted cells, which is thought to be biologically caused. We hypothesized that mechanical loss of cells from the contracting myocardium might actually be the main culprit. METHODS: Intramyocardial injections of fluorescent microspheres (10 microm) were carried out in both small and large animal models. The hearts of Lewis rats (250-350 g) received 3 x 10(6) microspheres injected into the left ventricular myocardium. Rats were divided evenly between two experienced operators. The nonbeating (n = 2) and beating (n = 5) hearts of piglets (7.5-7.8 kg) received 3 x 10(6) microspheres. The hearts were excised within 10 minutes, and the microspheres retained in the myocardium were quantified with fluorescent flow cytometry. RESULTS: In the beating-heart rat model, the microsphere retention rates after a single injection were similar with and without purse-string occlusion of needle puncture sites and slightly lower than after multiple site injections (6.19% +/- 4.05% vs 5.44% +/- 5.66% vs 8.83% +/- 3.29%). There were no significant operator-dependent differences. The retention rates in beating porcine hearts were higher than those in the rats (P < .05) but markedly lower than those in nonbeating porcine hearts (11.1% vs 67.4%). CONCLUSION: Mechanical leakage and washout may account for a major portion of cell loss after cell implantation, and efforts aimed at reducing mechanical loss in the beating heart may yield a greater benefit than those targeting biologic loss alone.

Animals↗

PubMed2005

Reappraisal of recent clinical trials of angiogenic therapy in myocardial ischemia.

We review the clinical trials of angiogenic therapy for myocardial ischemia, focusing on why the results are unsatisfactory in more recent larger and better designed trials. Critical reappraisal of such trials, in view of the pathophysiologic complexity of the angiogenic process at a molecular level, suggests that the strategy of therapies based on a single growth factor protein or gene may not be adequate for optimal therapeutic response.

Angiogenesis Inducing Agents↗

PubMed1998

The formalin test: a dose-response analysis at three developmental stages.

We investigated the behavioral response of rat pups to intraplantar injection of varying formalin concentrations using a time-sampling method. At 3 days of age, the response was monophasic and persisted for the whole hour, even at low formalin concentrations. Flexion, shaking and licking the injected limb and hind-limb kicking correlated strongly with log formalin concentration (r = 0.82); behavioral state was altered only at the highest concentration. The response on day 15 was also monophasic, but it waned in 30 min, even at the highest formalin concentration tested. Flexion, shaking and licking of the injected limb were strong pain measures (r = 0.83). The response at 25 days was biphasic, and the adult measures, paw lifting and licking, produced a good formalin concentration-effect relationship (r = 0.80). The log concentration-effect relationships for formalin at the three developmental stages and for adult rats were parallel, but between 3 days and 15 days of age, the relationship shifted to the right by 2.5-fold, and by a further 4-fold between 15 and 25 days, when the sensitivity to formalin-induced pain was similar to that in adults. The data describe efficient, quantitative measures of formalin-induced pain for developing rats, show that the pain response is log-linearly related to formalin concentration throughout development, and demonstrate that the sensitivity to formalin-induced pain is about 10-fold higher in neonatal rats than in weanlings. the data imply that there are major qualitative changes in pain processing as the nervous system develops.

Aging↗